First known extant species of Alavesia (Diptera: Atelestidae) in the Neotropical region : Alavesia leukoprosopa, sp. nov., from the southern Atlantic Forest, Brazil

2020·3.7 MB·English

by  Amorim, Dalton de Souza, author

AMERICAN MUSEUM NOVITATES
Number 3962, 12 pp. October 6, 2020
First known extant species of Alavesia (Diptera:
Atelestidae) in the Neotropical region:
Alavesia leukoprosopa, sp. nov.,
from the southern Atlantic Forest, Brazil
DALTON DE SOUZA AMORIM,! PAULA RAILE RICCARDI,?
AND JOSE ALBERTINO RAFAEL?
ABSTRACT
A first known extant Neotropical species of the atelestid genus Alavesia—Alavesia leuko-
prosopa, sp. nov.—is described from southeastern Brazil. The holotype (and only specimen so
far) was collected with a Malaise trap in an area with strongly impacted semideciduous seasonal
forest (dry forest) and open, entirely secondary vegetation. It was collected in mid spring, but
has not been collected again so far. Alavesia leukoprosopa shares some derived features with the
only two other extant species of the genus, known from the Brandberg Massif in Namibia, sug-
gesting that all three extant species may compose together a small clade separate from the bulk
of the Cretaceous diversity of Alavesia.
' Departamento de Biologia, FFCLRP, Universidade de Sao Paulo, Brazil.
* Departamento de Entomologia, Museu Nacional do Rio de Janeiro, Universidade Federal do Rio de Janeiro,
Rio de Janeiro.
> Instituto Nacional de Pesquisas da Amazonia, Manaus, Brazil.
Copyright © American Museum of Natural History 2020 ISSN 0003-0082
AMERICAN MUSEUM NOVITATES NO. 3962
INTRODUCTION
Five extant genera are now gathered under the family Atelestidae—Atelestus Walker, Acart-
eroptera Collin, Meghyperus Loew, Nemedina Chandler, and Alavesia Waters and Arillo. A
subfamily Atelestinae was originally proposed by Hennig (1970) within the Empididae s.L., later
raised to family rank by Chvala (1983). There is still no consensus about position of the ateles-
tids among the empidoids. Chvala (1983) proposed as ister group relationship between Ateles-
tidae and the Cyclorrhapha. Collins and Wiegmann (2002), Moulton and Wiegmann (2004,
2007), and Wahlberg and Johanson (2018) proposed Atelestidae to be sister of the remaining
Empidoidea based on molecular data, while Sinclair and Cumming (2006) accepted the family
as sister to the Hybotidae based on morphological data. In Sinclair and Kirk-Spriggs’ (2010)
phylogenetic study of the atelestids, Nemedina is proposed as sister to the remaining genera of
the family and was kept in a subfamily of its own, Nemedininae Sinclair and Cumming. Ala-
vesia is sister to the other three genera within a subfamily Atelestinae.
Alavesia was first described based on a middle Albian-upper Aptian amber fossil from
Spain (Waters and Arillo, 1999), to which a second species also from the Spanish Cretaceous
amber was later added (Pefialver and Arillo 2007). The original hypothesis by Waters and Arillo
(1999) and Penalver and Arillo (2007) was that Alavesia would belong to the Ocydromiinae
hybotids. Grimaldi et al. (2002) referred to undescribed species of the genus in Myanmar mid-
Cretaceous amber. Sinclair and Kirk-Spriggs (2010) transferred Alavesia to the family Atelesti-
dae. Besides the phylogenetic consideration of the Atelestidae, Sinclair and Kirk-Spriggs (2010)
also described the first two extant species known in the genus, from Namibia. The description
of the extant species brought a better understanding of the general morphology of the genus,
including the details of the male terminalia,
There were recent additions to the knowledge of the atelestids by Poinar and Vega (2020),
Jouault et al. (2020), and Zhang et al. (2020). Poinar and Vega (2020) described a Cretaceous
Myanmar amber species, placed in a new genus Neoalavesia Poinar and Vega—in the paper
assigned to the atelestids, but also referred to as an empidid. Jouault et al. (2020) described
another Cretaceous species of Alavesia of Myanmar amber and raised some hypotheses for the
origin of the genus. Zhang et al. (2020) described an additional species of Alavesia from Myan-
mar amber and the female of A. myanmarensis Jouault, Ngd-Muller, and Nel; they also discuss
the homology of sclerites of the male and female terminalia in the genus.
We now have a great expansion of our understanding of the diversity of Alavesia genus
with the description of nine additional species of the genus from Myanmar Cretaceous amber
material by Sinclair and Grimaldi (2020), They also synonymized Neoalavesia Poinar and Vega
(Poinar and Vega, 2020) to Alavesia.
To our initial amazement, we collected an additional extant species of Alavesia in south-
eastern Brazil. The discovery of a Neotropical species of the genus in South America is consid-
ered, nevertheless, consistent with an old clade with prior wide distribution in the world, now
with a relict distribution (Sinclair and Grimaldi, 2020). The presence of Alavesia in South
America adds a second genus to the diversity of Atelestidae in South America, the family also
including Acarteroptera from Chile (Collin, 1933). In this paper, we describe and illustrate this
2020 AMORIM ET AL,: FIRST SPECIES OF ALAVESIA (IN THE NEOTROPICAL REGION
first known Neotropical species of the genus and forward some initial comments on the posi-
tion of this species in Alavesia.
MATERIAL AND METHODS
The holotype is deposited in the Museu de Zoologia da Universidade de Sao Paulo, Sao
Paulo, Brazil (MZUSP). Pictures were taken with LAS software coupled to a stereomicroscope
and assembled in Helicon Focus 6. The terminalia were treated with 10% KOH at 40° C for 20
minutes, then neutralized in 1% acetic acid, and transferred to a microvial with glycerin, The
wing was mounted in Euparal between cover slips, then pinned beneath the specimen together
with the terminalia microvial. The morphological nomenclature follows Cumming and Wood
(2017), except for the ventral apodeme, referred to by Sinclair and Cumming (2006). Costal
sections also in Cumming and Wood (2017): section 1, between h and R,; section 2 between
R, and R,,,; section 3 between R,,, and R,,.; section 4 between R,,. and M,, Abbreviations are
provided in the legend of illustrations.
RESULTS
Alavesia Waters and Arillo, 1999
Type sPEcigs: Alavesia subiasit Waters and Arillo, 1999; 60, by original designation.
Dracnostis (from Sinclair and Kirk-Spriggs, 2010): Diminutive cell dm, M,,, and M,
greater than half the length of wing and widely divergent, postpedicel very long and lanceolate,
stylus three-articled, legs with parallel rows of minute setulae.
Alavesia leukoprosopa, new species
Figures 1-4
DracGnosis: Postpedicel slightly longer than scutum; face with whitish pruinosity; thorax dark,
with a whitish pruinosity; head and thorax setulae pale; legs yellow; M,,, slightly sinuose along its
length; ventrolateral of epandrium longitudinally sclerotized (fig. 4D, arrow); hypoproct longer than
cercus; postgonites not jointed mesally, long, curved anteriorly; hypandrium indistinct.
Description: Male. Body length, 2.2 mm (fig. LA). Head (figs. 1B-C): Frons black, with
some grayish pruinosity, face whitish with dense white pruinosity, occiput black on dorsal half,
thinly pruinose, grayish on ventral half, more densely pruinose. Gena very narrow. Ocelli on
slightly projected vertex, mid ocelli only slightly displaced anteriorly in relation to lateral ocelli.
Frons without setae, occiput with crown of yellowish postocular setae, face without setae. Eye
bare; eyes dichoptic, large, with a rather metallic reddish color. Scape whitish, pedicel pale yel-
low, postpedicel dark brown, Postpedicel greatly lengthened, longer than scutum; stylus short,
postpedicel about 5.8 length of stylus (fig. 3B). Maxillary palpus whitish, close to each other at
AMERICAN MUSEUM NOVITATES NO. 3962
at
FIGURE 1. Alavesia leukoprosopa, sp. nov., holotype. A. Habitus (scale bar = 0.1 mm). B. Head, frontal view.
C. Head, lateral view.
2020 AMORIM ET AL.: FIRST SPECIES OF ALAVESIA (IN THE NEOTROPICAL REGION
tip; labellum light brownish yellow at base, whitish toward apex; labrum slender, elongate.
Prementum well developed, whitish, setose.
Thorax (figs. 2A-B): Scutum and scutellum black, entirely covered with scattered pruinos-
ity, denser on postpronotal lobe; 3-5 rows of short acrostichals clearly separated from 4-6 rows
of short dorsocentral setae; pair of strong notopleurals, pair of long postalars, and an irregular
row of stronger postsutural. Antepronotum blackish, proepisternum ochre-yellow. Anepister-
num blackish; katepisternum mostly ochreous yellow, with small dorsoposterior brownish
mark, Anepimeron blackish, with brownish area along meso-dorsal suture, katepimeron reach-
ing ventral margin of thoracic pleura, weakly sclerotized, cream-yellow. Meron brownish yel-
low, dark brown along contact with metepisternum. Metepisternum blackish brown,
metepimeron dirty yellow, darker dorsally. Laterotergite and mediotergite blackish brown.
Elongate membranous area between anepisternum and katepisternum (fig. 2A, seta). Postpro-
notum densely microtrichose. One pale proepisternal seta present. Anepisternum densely pru-
inose, bare of setae; katepisternum shiny, no pruinosity or setae. Anepimeron, katepimeron,
metepisternum, metepimeron, laterotergite and mediotergite pruinose, devoid of setae. Meron
thinly pruinose, without setae. Halter stalk light brown, knob whitish, without setae.
Legs (fig. LA, 3C-D): Coxae whitish yellow, forecoxa lighter, femora light brownish yellow,
front and mid tibiae light brownish yellow, hind tibia darker, tarsi brownish yellow, darker
towards apex. Femora with longitudinal area devoid of setulae, but no furrow; tibiae with rows
of palisades with furrows in between. Hind tibia modified, more sclerotized than front and mid
tibiae, with conspicuous sensorial organ dorsally on basal fourth, bearing ellipsoidal opening
(fig. 3D).
Wing (fig. 3A): Length, 1.5 mm. Rather short compared to other congeneric species, oval
shaped. Costal sections 1—4: 10; 1.5; 6; 3. C without spines. H present, weakly developed, Sc rela-
tively long, extending beyond level of r-m, but incomplete; R, ending at distal third of wing, with
one basal (fig. 3A, arrow) and two distal sensorial pits; R,, ending at C slightly beyond tip of R,.
R,,; reaching C well before tip of wing, with three distal sensorial pits; M,,, almost as sclerotized
as R,,;, slightly sinuous along its length; cell dm present, small, restrict to basal third of wing,
cells br and bm also short; dm-cu connecting M,,, to M,, nearly transverse. Cell cua short,
CuA+CuP reaching wing margin; long conspicuous anal fold almost reaching wing margin.
Abdomen (fig. 1A): Tergites 1-5 blackish brown medially, yellowish at lateral margins,
sternites 1-5 pale brownish yellow, Tergites 6-7 more sclerotized along posterior margin, rather
dark brown; tergite 8 membranous, slender, bare of setation,
Terminalia (figs. 4A—D): Hypandrium not discernible. Gonocoxal apodeme slender and
greatly lengthened rod-like process, as long as ejaculatory apodeme, narrow in ventral view.
Postgonites not joined medially, striplike, very long and bent anteriorly. Phallus tube-like, short,
apex arched ventrally; ejaculatory apodeme long, articulated at base of phallus, posterior end
slightly broadened. Epandrium U-shaped, with slender dorsal bridge anteriorly to cerci; setae
concentrated along ventro-lateral margin; ventrolateral edge longitudinally sclerotized (fig. 4D,
arrow), basally attached to epandrium, projected apically. Surstylus subapical, divided into pair
AMERICAN MUSEUM NOVITATES NO. 3962
Cxl
Cxil
FIGURE 2. Alavesia leukoprosopa, holotype. A. Thorax, lateral view. B. Thorax, dorsal view. Abbreviations:
Ae, anepimeron; An, anepisternum; Cx I-III, front, mid, hind coxae; Kt, katepisternum; Ke, katepimeron; Lt,
laterotergite; Md, mediotergite; Me, meron; Mp, metepimeron; Mt, metepisternum; ps, prescutellar setae; sa,
supraalar setae; sct, marginal scutellar setae. Arrow points membranous area between the anepisternum and
the anepimeron, dorsally, and the katepisternum and the katepimeron, ventrally.
2020 AMORIM ET AL.: FIRST SPECIES OF ALAVESIA (IN THE NEOTROPICAL REGION 7
A | . at Rog
200 um %, ’
CuA+CuP
FIGURE 3. Alavesia leukoprosopa, holotype. A. Wing (abbreviations following Cumming and Wood, 2017).
B. Postpedicel and stylus. C. Hind leg, inner lateral view. D. Hind tibia, dorsal view, with tibial organ on basal
fourth. Arrow point basal R, sensorial pit. Abbreviation: af, anal fold; tf, tibial furrow.
AMERICAN MUSEUM NOVITATES NO. 3962
vapod
{
gonocox apod ej apod
FIGURE 4. Alavesia leukoprosopa, holotype. Male postabdomen. A. Dorsal view. B. Ventral view. C. Lateral
view. D. Ventral view (arrow points to heavily sclerotized blade at margin of epandrial ventral margin) (scale
bar 0.1 mm). Abbreviations: cer, cercus; ej apod, ejaculatory apodeme; epand, epandrium; gonocx apod,
gonocoxal apodeme; hyprct, hypoproct; pgt, postgonite; ph, phallus; sur, surstylus; v apod, ventral apodeme.
2020 AMORIM ET AL.: FIRST SPECIES OF ALAVESIA (IN THE NEOTROPICAL REGION 9
of pointed lobes, each dorsal lobe with pair of setae along inner margin. Hypoproct longer than
cercus, with setulae. Cercus sclerotized, ovoid, setose.
Female: Unknown.
TYPE MATERIAL: Holotype male, BRAZIL, Sao Paulo, Ribeirao Preto, University of Sao
Paulo — campus of Ribeirao Preto, in front Guest House, $21°09'54” W47°50'56", 593 m, Mal-
aise trap, 19.xi-3.xii.2019, PR. Riccardi and H.F. Flores leg. [MZUSP].
EryMo.oGy: The specific epithet of the species name refers to the face (Greek, prosepa)
with white (Greek, leukos) pruinosity in the described species.
REMARKS; This Neotropical representative of Alavesia differs in significant details from
both known extant species described from Namibia. The postpedicel is longer than in both
extant species of the genus. The scutum is yellow in A. brandbergensis, and black in A. daura
and A. leukoprosopa, sp. nov. As in A. brandbergensis, the legs in A. leukoprosopa are yellowish,
without the dark apex of mid and hind tibiae in A. daura. Compared to A. daura, the wing
shape is more rounded and the venation of the Neotropical species has a slightly wider cell c
and a more slender cell r,. Although Tergite 8 is about the same width, it is more membranous
than in A. brandbergensis, and without setulae. The male terminalia has the same general pat-
tern in the three extant species, but with some differences, The epandrium in A. leukoprosopa
is wider than in the remaining extant species. Also, the hypoproct and the postgonite in A.
leukoprosopa are much longer than in A. brandbergensis, bent ventrally in this latter species.
‘The connection between the gonocoxal apodemes and the hypandrium is indistinct in A. leu-
koprosopa, while these structures are visible in A. brandbergensis. Alavesia leukoprosopa seems
to be the only known species in the genus, extant or extinct, with a dorsal sensory organ at the
basal fourth of the hind tibia.
DISCUSSION
Sinclair and Kirk-Spriggs (2010) performed a phylogenetic study to place Alavesia using as
background the phylogenetic study of the empidoids by Sinclair and Cumming (2006) and by
redefining characters used earlier by Wiegmann et al. (1993) and Sinclair (1995), In the study by
Sinclair and Kirk-Spriggs (2010), Alavesia was used as a terminal, differently from other terminals
in the same analysis, which are species of the remaining atelestid genera and outgroups.
Alavesia leukoprosopa shares two synapomorphies established for Alavesia: dichoptic males
and discal cell shorter than the basal cells. A third feature taken as a synapomorphy of the
genus, a truncate Cu, is now known to be absent in some of the Myanmar amber Alavesia
species. A long postpedicel is present in different empidoid clades. In Meghyperus the postpedi-
cel is wide at the basal half and longer than twice the pedicel length, Nemedina and Acarterop-
tera also have the postpedicel more than twice the pedicel length, but not as long as in
Meghyperus and not even close to the condition seen in Alavesia species. The species from
Myanmar amber described by Sinclair and Grimaldi (2020) also show a variety of conditions
of the antenna, all with a long postpedicel. In this sense, the short postpedicel in Atelestus may
be secondary among the atelestids.
10 AMERICAN MUSEUM NOVITATES NO. 3962
FIGURE 5, Collecting site (with Malaise trap) of Alavesia leukoprosopa, campus of the Universidade de Sao
Paulo at Ribeirao Preto, Brazil.
The holotype of A. leukoprosopa was collected in the northwest of the State of Sao Paulo,
an area that has intersections between the semideciduous seasonal forest (also referred to as a
dry forest) and cerrado elements (see, e.g., Amorim and Santos, 2018). The collecting site is at
the university campus and has a mix of highly impacted original forest patches and exotic
vegetation. One single male was collected mid spring of 2019 on the campus in a Malaise trap.
No other specimens of the species have been collected to the second half of the summer of
2020. It may be the case that the species has a very restricted phenology. This will be verified
by continued collecting through 2020. The two extant known Afrotropical species of Alavesia,
on the other hand, were collected in Namibia, on the Brandberg Massif, which is a transition
between savannah and semidesert. This area is actually home to extant species of scorpions
that hardly could have questioned their Gondwanan origin (Prendini, 2003). The clade of
Afrotropical bothriurid scorpions are also related to a South American / Australian lineage
living in dry environments (Prendini, 2003).
The species of Alavesia now known from the Cretaceous of Spain (Waters and Arillo, 1999;
Penalver and Arillo, 2007), from the Cretaceous of Myanmar, and the extant Namibia and Neo-
tropical species show an impressive array of morphological variation. Not only are there innumer-